Headlight.



.E. L. CLARK.

.HEADLIGHT. APPLICATION FILED ocr. 16. I914.

1,136,507, Patented Apr. 20, 1915.

WITNESSES [NV/5N TO R huww/Jg EMERSON L. CLARK, 01 LAKEWOOD, OHIO.

HEADLIGHT.

Specification of Letters Patent.

Patented Apr. 20, 1915.

Application filed October 16, 1914. Serial No. 866,961.

To all whom it may concern Be it known that I, EMERSON L. CLARK, a

citizen of the United States, residing at Lakewood, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Headlights, of which the following is a full, clear, and exact description.

The object of my invention is to secure an improved headlight for vehicles, such automobiles, which will give an abundance of light on the road ahead, but projected in such a. manner that no glare or blinding is caused to approaching drivers or pedestrians. I accomplish this result by a peculiarly designed reflector which projects the greater part of the light below the horizontal axis of the lamp and only permits the scattered light and that coming directly from the lamp, and therefore uninfluenced by the reflector, to issue into the region above the horizontal axis. This direct un reflected light can further be excluded or reduced it desired by frosting or opaqueing the portion of the globe through which it issues or by placing an obstruction in its path near the lamp where little of the light flux from the reflector will be encountered. I secure the :bove result by making a reflector the upper and lower half of which have the following relations:

The upper half is an approximate half paraboloid, made half by d viding a paraboloid by a plane through the axis of the paraboloiiil perpendicular to the plane generated by the rotation of the directrix about the axis of the paral'ioloid. The lower halt of the reflector similarly made from a paraboloid which an" be similar ditl'erent in curvature than the paraboloid of the half, The lmver half of the reflector 'ta tot-us approximately on the pper half of the reflector but in tocal point of said upper half. ource which should be fairly i-ompau iu'rordiug to the concentration des ind is i cod between these two 'foe With n'ient the light striking thizipper ilector will nearly all fall below 1: plane through the axis 0% the 'l the light striking the loner source is behind the fociis below said lH upper ncrease the angl of s 1 diffusion at the reflected light. Increasing the distance between the two foci above mentioned will increase the angle of depression of the light below the horizontal. It is easy by well known means to vary the distance between the two foci from the drivers seat, thus changing the distribution of the illumination.

Although I have described my invention as consisting of two separate half paraboloid relleetors, it is obvious that the same optical surfaces can be made in one piece; the lower half having its focus in front of the focus of the upper half. This latter type, however, not permitting of adjustment of the distance between the two foci.

In the drawings the figure is a diagrammatic representation of a vertical section through the axis of the reflector.

A is the section of the upper reflecting surface, B is the section of the lower reflect- 'ing surface, K is the axis of the two reflecting surfaces.

l is the focus or region of concentration for axially parallel light on the reflector A; l is the corresponding point of reflector B.

1 represents the light source between C and D,

I is any point on the reflecting surface A, Q any point on the reflecting surface B.

CPM is a path of light issuing from the focus C anstriking P. It is to be noted that PM is approximately parallel to the axis K.

Flll is the path of a bundle of light rays from the source F striking P. 'It to be noted that lll diverges t'rom PM toward the axis K,

' issuing 'i'rom the to for B at it -,i:' x mate y para handle or ight rays ,i from t "1 aourcr i it is to be noted that the rays 7 diwrge from Q0 away from the axis K. it is thus possible by surrounding a light source i with the half poraboloids represcntrd y A and ll placed with their f ci as i throw all of the the axi which al for l"-ili4 :il-ovc stated. ll ring now inscrib d my nvention, what i as and wish to protect by Letl ght the combination of two we; con isting of ap a-o t t halt pa aliol iius or revolution set with thin and occupying axes approximately coincident but with the focus of one in advance of the focus of the other.

2. In a headlight the combination of two reflecting surfaces, each having a region of concentration for light parallel to its axis, set with their axes approximately coincident but with the region of concentration of one set in advance of the region of concentration of the other.

3. In a headlight the combination of two reflecting surfaces, each having a region of concentration for light parallel to its axis, set with their axes approximately coincident but with the region of concentration of one set in advance of the region of concentration of the other, and a light source placed between said regions of concentration.

4. In a headlight the combination of two reflecting surfaces, each having a region of concentration for light parallel to its axis, set with their axes approximately coincident, diflerent angular space around the axis, and with the region of concentration of one displaced along the axis with respect to the region of concentration of the otherreflecting surface;

5. In a headlight, a reflector provided with two angularly displaced reflecting portions having foci which are located approximately on the axis of the reflector and are displaced one in advance of the other.

6. In a headlight, a reflector provided with two angularly displaced reflecting portions having foci which are located approximately on the axis of the reflector and are displaced one in advance of the other, and a source of light between said foci.

7. In a headlight, a reflector havin a reflection surface composed of two ha f sections having adjacent marginal edges approximately in a diametrical plane and the rear central portion of one being displaced V axially with respect to the other.

8. In a headlight, a reflector having a reflecting surface composed of two approximate half-paraboloids occupying difl'erent angular positions and set with their axes substantially coincident, one half-paraboloid being displaced axially with respect to the other.

9. In a head-light, a reflector provided with two reflecting portions with their ax'es approximately coincident and one portion located above the other, each portion having a region of concentration for light parallel to its axis, the region for the upper portion being in the rear of the regionfor the lower portion, and a source oflight between said regions.

In testimony whereof, I hereunto aflix my signature in the presence of.

EMERSON L. CLARK.

Witnesses:

EARL W. CLARK, MAE M. CLARK. 

